The field of the invention relates generally to gasification systems, and more particularly, gasification systems for producing synthetic natural gas (SNG) from low rank fuels.
Feedstock, such as coal, petroleum coke, biomass, wood-based materials, agricultural wastes, tars, coke oven gas and asphalt, and other carbon-containing items may be gasified for use in the production of electricity, chemicals, synthetic fuels, and for a variety of other applications. Gasification generally involves reacting a carbonaceous fuel and oxygen at a very high temperature to produce syngas, a fuel containing primarily carbon monoxide and hydrogen. Syngas typically burns more efficiently and cleaner than the fuel in its original state before gasification. The syngas maybe used for power generation, chemical production, and any other suitable application.
Some carbon containing solid feedstocks commonly known as low rank feedstocks, however, are unsuitable and/or inefficient for use in connection with some known gasification systems. Low rank feedstocks are typically undesirable due to their low heating value and inherently higher oxygen content as compared to fuels typically used in gasification systems. In addition, low rank fuels typically form a very watery slurry, and typical entrained gasification systems are inefficient in producing syngas with such fuels.